engleski

Stability estimation of the Ilizarov external frame by electronic teodolite

Deformations of the external fixater used for medical purposes were assesed automatically by means of electronic teodolite and PC notebook. The stability of classic and hybrid forms of the Ilizarov external frame was compared. a plastic femoral bone model was attached to the surface as a console and sawed into the subtrochanteric region. Loading was exerted by static force and static moment of different directions and magnitude. It produced dislocations of dots marked on the bone model and the extraosseus parts of external fixater. Measurements were performed in three space directions by means of an electronic teodolite. he direction and length of dominant shift were estimated by vector analysis. We compared certain shifts at classic and hybrid form of Ilizarov external frame. The promminent values of dislocation at dots on the bone model and the extraosseus parts of the external frame were defined, based on the obtained results. The results for both external frame types were compared. They were quantified and determined numerically: certain shifts in the classic form of external frame about 3 to 5 times greater than in the hybrid one. A shift of the bone part above the fracture site toward the part below the fracture site was calculated. This provoked pain in patients. A previously noted fact was confirmed: the hybrid type of external fixater is more stable than the classic one. Electronic teodolite is a reliable instrument for the estimation of fixateur frame stability. The described method will enable testing of any newly develped constructions of external frames.

electronic teodolite; external fixater

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